1,3-propanediol is an alcohol (represented by CH2OHCH2CH2OH) having three carbons and two hydroxyl (—OH) groups and can be used as a monomer for polymers such as polyesters or polyurethanes. In addition, 1,3-propanediol can be used as an additive for improving properties of cosmetics and personal care products. Particularly, polytrimethylene terephthalate (PTT) which is a linear aromatic polyester produced by polymerization of 1,3-propanediol and terephthalic acid has a unique twisted linkage called kinks created on a semi-crystal molecular structure of a polymer chain, and thus exhibits excellent elasticity and shape stability. Due to such a structural property, PPT can be used in a broad range of applications such as fibers, packages, films, non-woven fabric structures, engineering plastics, and the like.
1,3-propanediol can be synthesized by chemical synthesis and biological synthesis. As a chemical method, 1,3-propanediol can be produced by hydrogenation using ethylene oxide or acrolein as a raw material. However, this method has problems such as high cost and production of wastes containing environmental contaminants.
As a biological method, 1,3-propanediol can be produced from fermentation by recombinant Escherichia coli using corn derived sugars as a raw material or from fermentation by a 1,3-propanediol producing strain (1,3-propanediol natural producer) using glycerol as a raw material. A microorganism (recombinant Escherichia coli) which produces 1,3-propanediol using sugars derived from biomass such as corn was developed by DuPont, USA and has been used in industrialized production (WO 2001/12833). On the other hand, microorganisms capable of producing 1,3-propanediol using glycerol as a raw material has been known for over a century. Examples of such strains can include microorganisms belonging to genus Klebsiella, genus Enterobacter, genus Clostridium, genus Citrobacter, genus Lactobacillus, and the like. Such microorganisms produce 1,3-propanediol by a reductive metabolic pathway of glycerol and are provided with a carbon source and an energy source required for growth and a coenzyme (NAHD) required for 1,3-propanediol production by an oxidative metabolic pathway.
Klebsiella pneumoniae as a representative 1,3-propanediol producing microorganism is a gram negative (G(−)) bacterium, and has an excellent property of producing not only 1,3-propanediol but also 2,3-butanediol. This property can be a limitation on production of 1,3-propanediol using glycerol as a raw material since 2,3-butanediol has a boiling point similar to 1,3-propanediol, which creates problems such as making purification procedures difficult and lowering final purification yields. In order to solve these problems, research has been performed to construct variants having only a reductive metabolic pathway of producing 1,3-propanediol by employing a genetic recombination technology, i.e., by blocking an oxidative metabolic pathway of producing byproducts among glycerol metabolic pathways so as not to produce oxidative metabolic byproducts such as 2,3-butanediol. However, this method had a problem of poor 1,3-propanediol productivity, making commercial application difficult (Korean Patent Application No. 10-2008-0122166).
As a result of earnest investigation aimed at developing a recombinant microorganism capable of producing less oxidative metabolic byproducts including 2,3-butanediol upon production of 1,3-propanediol, the present inventors identified that a recombinant microorganism in which specific genes are deleted produces decreased amount of byproducts without lowering production yield and productivity of 1,3-propanediol. Based on this finding, the present invention has been completed.